Shock absorber



M. w, W230 mmm J. T. FERRES SHOCK ABSORBER Filed Nov. 24, 1920 INVENTOR.

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it it till it ll application filed lt'oveniber To all whom may concern lle it lrnown that l, diarrnnr T. lfnmuas, a citizen of the United States. and a resident of lies ll geles, in the county of lies hugeles, ll'tate of @dllfOlnltt have invented certain new and uset'ul improvements in tlhock Absorbers, oi? which the following is a speci tication.

This invention relates to shock absorbers ot the character employed in connection with motor vehicles for minimizing the shoclrs transmitted through the wheels of the vehicle to the axles, and an object at the invention is to produce an ellective shock absorber r comparatively simple construction,

Another object is to provide a shoclr absorber ot which the parts will not be liable to become disauranged while in use.

Another object is toutiliae air as the shock absorbing cushion .tlnother object is-to provide for thorough lubrication oil the plunger and cylinder walls, so as to minimize wear of the plunger and cyli" der.

it still hirther object is to make provision tor yieldingly checlrinp; the downward mo tion out the plunger when the vehicle wheels are subjected to a shoclt suli'ieiently great to tend to drive the plunger against one end ot the cylinder.

The accompanying drawings illustrate the invention 1' l 'i enre l. {is vertical mid-section ot a shoclr absorber embodying" the invention one oil the attaching members being partially brolren away to contract the view;

l ipgure 9) plan section on the line indicated by a -a2 Figure l; and

Figure 3 is a plan section on the line indicated by Figure it There is provided a cylinder 1 and slidably tittiing therein is a plunger 2 of any suitable construction. in the particular instance shown in the dravvinpgs the plunger 2 is provided with. annular grooves 3 in which are disposed piston rings l so to ma be a comparatively close sliding lit between the plunger and the cylinder wall. The plunger is provided with a stemh which passes through through an opening 6 in the head 'l of the cylinder. To minimize leakage ot air from the cylinden the head i is provided with a stuiiing hot: 8 of an desired constructiom the packing in sai stalling but being indicated at at, rate. serial no.

The plunger 2 is provided with a port or ports 10 extending from the trout face to the rear taco thereof. Positioned in the cylinder 1 between the plunger 2 and the head 7 is a valve 11 adapted to close the ports 10 when the plunger moves rearwardly toward the head 7. lit the shoclt absorber be positioned with the head 7 uppermost in the drawlugs; gravity and the air pressure upon the valve, upon upward movement of the plun gel. may be relied upon to close the valve; but it is preferable to employ a spring; to hasten the closing action of the valve and. therefore, such a spring; is shown at The spring 12 is preferably conical. so that may be compressed into a minimum space thus melting it possible to employ a relatively short cylinder:

The stem 5 is provided with an axially eittending; ductlit which opens through the inner end of the stem so as to communicate with the air chamber 14: formed by the space in the cylinder in trout ofthe plunger. The duct 13 communicates through a port or ports 15 with the air chamber 18 formed by the space in the cylinder behind the plunger. The ports 15 are of small cross sectional area relative to the ports 10., so that when .l3l18 valve 11 is closed during the movement of the plunger rearwardly toward the head i" the air in the chamber 16 can escape but slowly therefrom through the ports 15 in order to retard the rearward movement of the plunger.

W hen the plunger 2 moves forwardly to a predetermined position, the trout tace of the plunger, which is recessed as indicated at 18, engages a second valve 19 adapted when the plunger is in such predetermined position, to close the ports 10, thus preventing further escape oi air from the chamber 14 excepting through the duct 13 and ports 15. When the ports 10 are thus closed by the valve l9, it is evident that the air in the chamber 14ll'orms a cushion to yieldingly oheclt the movement ot' the plunger toward the head 17. The valve Jill is shittably mounted on a post 20 and is yieldingly held against a shoulder 21 on the post by a spring; 22; which is preiterably conical tor the same reason as that given in the above description of the spring 1%. I

The elements above described constitute by themselves an operative device and the o oration thereot will now be described.

Tie stem ti and cylinder head I l he lid till

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ltltl ltd lvehicle wheels relatively move from each other the plunger 2 will move rearwardly or toward the head 7 and so that when the chassis and wheels move relatively toward each other the plunger will move toward the valve 19. From this it is clear that when the vehicle wheels strike an obstruction or a rut the lunger 2 will move toward the' valve 19, tius tending to compress air in the chamber 14, and this air pressure opens the valve 11 so as to permit air to escape from the chamber 14 into the chamber 16 by way of the ports 10.

Assuming, for example, that the shock is relatively slight, so that the plunger does not engage the valve 19 but starts to move away from said valve, as soon as retraction of the plunger begins the valve 11 closes, thus tending to compress air in the chamber 16, and such air forms a cushion tending to retard retraction of the plunger and hence tending to retard the separating movement of the chassis and wheels of the vehicle. However, the air in the chamber 16 is permitted to slowly escape so that the. vehicle body andwheels can return to their normal positions relative to each other and such escape of the air takes" place through the ports 15 and ducts--13, the air thus escaping being returned to the chamber 1 1. From this it is clear that under relatively slight shocks the vehicle axle and chassis will approach each other just the same as when the shock absorber is notused, and that an air cushion causes retardation in the subsequent separation of the axle and chassis.

Now assuming, for example, that the shock to which the vehicle is subjected is sufiiciently strong to cause-the plunger 2 and valve 19, to engage each other and thus close theports 10, air will cease "toescape from the chamber 16 excepting through the relatively small ports 15, so that the aircushion inthe chamber 16 will check or retard the further forward movement of the plunger toward the head'l'Z. The movement of the chassis and axle toward each other is thus stopped gradually, so that damage to the vehicle and the shock absorber is avoided.

Further "features of the invention, not absolutely essential to its operation, will now be described. The post 20 is tubular, the axial duct being shown at 23, and the post thus constitutes a lubricant-discharge nozzle which is of less diameter than the duct 13, so that when the plunger moves forwardly sufficiently far the nozzle can enter the duct 13. To perform its function, it is not necessary that the nozzle enter the duct 13, hut this makes it possible to have the cylinder 1 or mmnnnm length. Near its lower end the duct 23 communicates by lateral ports 24 with the chamber 14, so that lubricant, indicated at A in Figure 1, can pass into the duct 23 from the chamber 14. lVhen the plunger moves into engagement with the valve 19, the pressure of air upon the surface of lubricant outside of the nozzle 20 overbalances the air pressure in the duct 13, thus causing the lubricant to discharge from the nozzle into the duct 13. The inbricant thus discharged from the nozzle will gather upon and run down that portion of the wall of the duct 13 above the ports 15 and, consequently, will discharge through the ports 15 into the chamber 16 to lubricate the friction surfaces of the cylinder and plunger.

lfhe lubricant A may be run into the cylinder through a filling opening 25 normally closed by a plug 26. Preferably extending into the lower end of the duct 23 is a wick 27, and said wick passes through a duct 28 in the head 17. The duct 23 opens into a ball socket 29 in which its the ball 30 of a connecting member 31. lubricates the universal joint formed by the socket 29 and ball 30.

It is preferable to enclose the portion of the stem 5 which projects from the stuffing box 8 and for this purpose a tubular flexible cover 32 is provided, said cover being suitably fastened at one end to the stem 5 and at its opposite end to the head 7. in the instance shown in the drawings, the cover 32 is provided at its ends with rings 33,3 l,r espectively,the ring, 33 engaging in an annular recess 35 in the stem 5, and the ring34c engaging an annular recess 36 i n the periphery of the cylinder head 7. The cover 32 is of sufiicient length to permit of: the full outward movement of the stem, and when the stem moves inwardly the cover arranges itself in folds, as clearly shown in Figure 1.

1 claim:

1. in a shock absorber, the combination of a cylinder, a lubricant in the 1 wer portion oi? the cylinder, there being an air space in the cylinder above said luhric it, a plunger in the cylinder having a port, a atom. for the plunger extending through one of the cylinder heads and having a duct communicating with the space in. the cylinder in front of the plunger and having a port opening from the duct to the cylinder behind the plunge being of less cross sections first port, and a valve for adapted to be closed by the air prc hind the plunger and to be ope air pressure in front of t 1e 2. in a shoclr absorber, of cylinder, a plunger in i Q. ing a port, a stem for the through one of the cylinti the last port nbination lindcr haw .1. encircling The wick 27 thus spare in the ing a duct communicating with the space in the cylinder in front of the plunger and havinga port opening from the duct to the space in the cylinder behind the plunger, the last port being of less cross sectional area than the first port, a valve for the first port adapted to be closed by the air pressure behind the plunger and to be opened by the air pressure in front of the plunger,

and a second valve for closing the first port when the plunger moves forward to a predetermined position.

3. In a shock absorber, the combination of a cylinder, 3, plunger in the cylinder having a port, a stem for the plunger projecting through one of the cylinder heads, and a tubular flexible cover surrounding the stem and secured thereto at one end and secured at its opposite end to the adjacent head of the cylinder, means to permit a relatively small leakage of air from the space behind the plunger to the space in front thereof independently of the port, and a valve for the port adapted to be'closed by the air pressure behind the plunger and to be opened by the air pressure in front of the plunger.

4. In a shock absorber, the combination of a cylinder, a plunger in the cylinder havmg a port, means to permit a relatively small leakage of airfrom the space behind the plunger to the space in front thereof independently of the port, a valve for the port adapted to be closed by the air pressure he hind the plunger and to be opened by the air pressure in front of the plunger, a second valve for closing the first port when the plunger moves forward to a predetermined position, and a lubricant in the cylinder beneath the last valve, there being an air space in the cylinder above the lubricant.

5. In a shock absorber, the combination of a cylinder, a plunger in the cylinder having a port, means to permit a relatively small leakage of air from the space behind the plunger to the space in front thereof independently of-the port, a valve for the port adapted to be closed by the air pressure he hind the plunger and to be opened by the air pressure in front of the plunger, a second valve for closing the port when the plunger moves forward to a predetermined position, means yieldingly holding the second valve in said predetermined posit-ion, and a lubricant in the cylinder beneath the last valve, there being an air-space in the cylinder above the lubricant.

6. In a shock absorber, the combination of a cylinder, a plunger in the cylinder having a port, a stem for the plunger extending through one of the cylinder heads and having a duct communicating With the space in the cylinder in front of the plunger and having a pgrt opening from the duct tothe space in the cylinder behind the plunger, the last port being of less cross sectional area than the first port, a. valve for the first port adapted to be closed by the air pressure behind the plunger and to be opened by the air pressure in front of the plunger, a second valve for closing the first port when the plunger moves forward to a predetermined position, and a nozzle discharging towardthe duct, the nozzle duct communicating by a port with the space in the cylinder in front of the plunger.

7. In a shock absorber, the combination of a cylinder, a plunger in the cylinder having a port and having a stem projecting through one end of the cylinder, a lubricant in the cylinder, a connecting member, means forming a socket on one end of the cylinder, there being a duct leading from the socket into the cylinder, a connecting member having a ball at one end fitting in the socket, and a valve operating to close the port when the plunger moves toward one end of the cylinder, said valve being opened by fluid pressure when the plunger moves toward the opposite end of the cylinder.

Signed at Les An eles, California, this 17th day of November 1920.

JEFFREY 'll. FERRES.

Witnesses:

GEORGE H. HILES. lb. BELLE Western. 

